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    <title>Document</title>
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<script>
    var r=prompt('请输入圆的半径：')
    r=parseFloat(r)
    var c=2*3.14*r
    var s=3.14*r*r
    console.log('圆的周长为'+c.toFixed(2));
    console.log('圆的面积为'+s.toFixed(2));
</script>